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Antimicrobial Activities of Volatile Components and Various Extracts of Dictyopteris membranaceae. and Cystoseira barbata. from the Coast of Izmir, Turkey

Abstract The methanol, dichloromethane, hexane, chloroform, and volatile components of Dictyopteris membranaceae. (Stackhouse) Batters (Dictyotaceae) and Cystoseira barbata. (Good et Woodw.) J. Agardh (Cystoseiraceae) were tested for their antimicrobial activities (four Gram-positive bacteria, four Gram-negative bacteria, and Candida albicans. ATCC 10239). Five compounds were identified in the volatile oil of D. membranaceae. accounting for >85% of the composition of the volatile oil. Twenty-eight compounds were identified in the volatile oil of C. barbata. accounting for >67% of the composition of the volatile oil. Major components were 6-butyl-1,4-cycloheptadiene (43.21%) for D. membranaceae. and docosane (7.61%) and tetratriacontane (7.47%) for C. barbata.. Many compounds in the volatile oil of C. barbata. were identified as hydrocarbon compounds. The volatile oils of these algae did not remarkably inhibit the growth of tested microorganisms. However, the hexane extracts showed more potent antimicrobial activity than methanol, dichloromethane, and chloroform extracts.

Antimicrobial activity of volatile component and various extracts ofEnteromorpha linza (Linnaeus) J. Agardh from the coast of Izmir, Turkey

The methanol, dichloromethane, hexane, chloroform and volatile components ofEnteromorpha linza were testedin vitro for their antimicrobial activity against five Gram-positive, four Gram-negative bacteria andCandida albicans ATCC 10239. GC-MS analysis of the volatile components ofE. linza resulted in the identification of 35 compounds which constituted 84.76% of the total compounds. The volatile components ofE. linza consisted of n-tetratriacontane (8.45%), 1-heptadecanamine (6.65%) and docosane (6.46%) as major components. The methanol and chloroform extracts showed more potent antimicrobial activity than hexane and dichloromethane extracts. The volatile oils of these algae did not remarkably inhibit the growth of tested microorganisms.

Epizoic Freshwater Algae on Emys orbicularis (Testudinata: Emydidae) from the Central Anatolia Region of Turkey

ABSTRACT We surveyed the epizoic algae growing on Emys orbicularis from several sites in the Central Anatolia region of Turkey during the nesting season (May-August) of 2005. Fifty-three algae species were found on carapaces of thirty-five E. Orbicularis, with considerable variation in the algal communities from different sites.

The effect of UV-A (352 nm) stress on chlorophyll fluorescence, chlorophyll a content, thickness of upper cortex and determinate DNA damage in Physcia semipinnata

In the present study, Physcia semipinnata samples were exposed to UV-A (352 nm) in 20 J m(-2) for 24 h, 48 h and 72 h to seek the alterations in the PSII photosynthetic quantum yield, thallus anatomy and DNA mutation rate in response to radiation. The Fv/Fm ratio decreased in P. semipinnata following exposure to UV-A for 24h, 48 h and 72 h. The data of the present study reported that Chla degradation occurred by exposition of UV-A for 24 h, 48 h and 72 h. Photobiont size and thickness of upper cortex layer also showed a gradually decrease in P. semipinnata thallus sections during 24 h, 48 h and 72 h. The thickness of the upper cortex layer, exposed to UV-A for 72 h, of P. semipinnata thallus reduced 64%, compared with control. The random amplified polymorphic DNA (RAPD) technique was used to detect DNA damage. The main changes observed in the RAPD profiles resulted in both appearance and disappearance of different bands and variation of their intensity. According to RAPD assay, the genetic distance between the control group and 24h , 48 h and 72 h UV-A exposed, groups was found 56%, 78% and 84%, respectively.

Abscisic acid and polyamine contents in the lichens Pseudevernia furfuracea and Ramalina farinacea

The levels of endogenous abscisic acid and total polyamine contents (putrescine and spermidine) were studied in two lichen species differing in desiccation tolerance. ABA and polyamine contents showed significant differences between air-dried and water-treated thalli of Pseudevernia furfuracea and Ramalina farinacea. The levels of putrescine (put) and spermidine (spd) in water-treated P. furfuracea thalli were found higher than in dry samples. The values for spd were almost threefold and for put almost 1.4-fold higher than in airdried samples. The levels of put and spd in water-treated R. farinacea were lower than in the air-dried samples. The lowest values for spd and put were almost 33-fold and 2.8-fold less, respectively. ABA contents of water-treated P. furfuracea and R. farinacea increased by 2.65% and 25.5% when compared with air-dried thallus.

Effects of chromium VI stress on photosynthesis, chlorophyll integrity, cell viability, and proline accumulation in lichen Ramalina farinacea

In order to contribute to understanding of the response to metal stress, Ramalina farinacea (L.) Ach. was treated with different concentrations of chromium (VI) (5, 15, and 30 mM of K2CrO4) for 1, 3, and 24 h, and alterations in the photosystem II photosynthetic quantum yield, pigment content, integrity of chlorophyll, cell viability, and proline accumulation were investigated. Significant alterations of the photosynthetic quantum yield (Fv/Fm) ratio were observed in response to the increase in chromium concentration. The Fv/Fm ratio decreased in R. farinacea following 24-h treatment with 30 mM Cr6+ solution. In present study, in both control and other plant groups treated with 5 mM Cr6+, the Chl a/b ratio was approximately within the range of 2.0–3.5. However, this ratio significantly decreased for the samples treated with 15 (exposure period of 24 h) and 30 mM; (exposure periods of 3 and 24 h) Cr6+. We also showed that cell viability of samples treated with 15 and 30 mM Cr6+ significantly decreased. Accumulation of metal resulted in proline accumulation in R. farinacea thalli; however, when photodestructive effects on photosystem II occurred, proline intracellular concentration declined. On the basis of these results, we suggest that proline accumulation might not be the stress marker during heavy metal stress.

The Shape and Size Effect of the Diatom Frustule Addition on the Compression Behavior of an Epoxy

The effects of the Achnanthes taeniata and the diatomaceous earth (diatomite) frustules addition on the compressive strength of an epoxy matrix were investigated experimentally. The Achnanthes taeniata frustules having relatively high length/diameter aspect ratio (2-4) were isolated and cultured in laboratory. While the as-received commercial natural diatomite frustules were non-homogenous in shape and size. The filling epoxy matrix with ~6 wt% of commercial natural diatomite increased the compressive strength from 60 MPa to 67 MPa, while the Achnanthes taeniata frustules addition increased to 79 MPa. The increased compressive strength and modulus of the the Achnanthes taeniata frustules filled epoxy was attributed to the higher aspect ratio and relatively strong bonding with the epoxy matrix. The more effective load transfer from the matrix to the Achnanthes taeniata frustules associated with the enhanced interface bonding was also proved microscopically. The frustules were observed to pull-out on the fracture surface of the Achnanthes taeniata frustules filled epoxy.